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There is a well-established correlation between stress resistance and life extension across diverse species. This correlation has been used in the past to discover long-lived strains of invertebrates by selecting for mutants resistant to environmental stress such as heat or reactive oxidants. Here, we tested whether mutations in mouse genes that convey paraquat resistance have functional homologs in the nematode Caenorhabditis elegans that convey similar paraquat resistance and also life extension. We obtained worm strains mutant for genes that modulated paraquat resistance in mouse embryonic stem cells. Each strain of worms was tested for paraquat resistance as well as life span. We found that some of the genes previously discovered to provide paraquat resistance in mice do in fact also modulate paraquat resistance in worms, but only a minority of the worm mutants tested also display increased longevity. We conclude there is partial conservation of the relationship between paraquat resistance and life span across mice and nematodes.
ELUCIDATING THE MECHANISM OF MTDNA PURIFYING SELECTION IN THE GERMLINE USING C. ELEGANSAditi Trivedi, Sagen Peterson, Joel Rothman.
University of California Santa, Barbara, Santa Barbara, CA.
Inheriting healthy mitochondrial DNA (mtDNA) from the maternal line is necessary for proper energy metabolism, growth, and organismal viability. The mechanism of purifying selection, a process by which favorable mtDNA molecules are preferentially inherited while the mutated are degraded, is not completely understood yet is an essential check against accumulation of defective mitochondria. In this project, we are investigating the germline apoptotic hypothesis as a mechanism for purifying selection in C. elegans. Specifically, this involves transferring mitochondria from laboratory WT strain N2 into a strain called LB138, which carries complementary mtDNA deletions (uaDf5 and w46). Then, through a screened selection condition that we are currently developing, we will select for the progeny that have successfully incorporated the N2 mitochondria. Preliminary data suggests Chloramphenicol as a promising candidate for this selection condition. Using qPCR, we can then quantify the efficiency at which subsequent generations preferentially incorporate the N2 mitochondria and, thus, the rate at which purifying selection occurs. In addition, we are developing apoptotic mutant strains (ced-3, ced-13) to test the proteins involved for a more complete understanding of the mechanism using a similar method. If purifying selection is occurring as hypothesized, we should observe greater N2 mitochondrial DNA qPCR signal more quickly for the LB138 strain than the ced-3 or cedmutants, suggesting the necessity of these apoptotic proteins in purifying selection and, specifically, suggesting apoptosis in the germline as a key regulator of mtDNA inheritance. These results will show tremendous promise towards the understanding, treatment, and cure of mitochondrial myopathies.
THE GENETICS OF DYSLEXIAIsaye Barton, Wendy Raskind, Mark Matsushita.
University of Washington, Seattle, WA.
Evidence supports the belief that dyslexia has a genetic basis. However, the factors in the human genome that contribute to the disorder such as common DNA variants and/or rare mutations have not yet been identified with certainty. Genetic alterations that cause amino acid changes have been found in some affected individuals, but the implications are unclear. This project seeks to find genetic contributors to component phenotypes of dyslexia, for example, spelling ability, by studying whole families. Using the genotypes of 1,200 members of 357 families, we have been able to identify and refine candidate regions on several different chromosomes that may contain these genetic risk factors. We will use statistical genetics approaches to narrow these regions further and target for more detailed analysis variants in the genes that lie within these regions.
The dorsal vessel in Drosophila melanogaster is similar to the vertebrate heart in early embryonic development.
In Drosophila, there are several genes necessary for the development of the dorsal vessel that are homologous to vertebrate genes. These common elements between Drosophila and vertebrates allow knowledge from studying the dorsal vessel to further our understanding of vertebrate heart development. Currently, we are trying to find the enhancer region of an alkaline phosphotase ortholog that we hypothesize is involved in the formation of ostia, which are inflow tracts that allow for hemolympth to enter the heart. We have identified possible enhancer regions for this gene and, by using a lacZ reporter, we have created enhancer-reporter constructs. These constructs are then injected into Drosophila embryos to create transgenic flies. At this point, we have found that 5 of the regions do not exhibit enhancer activity for the ortholog, and 2 other regions are still being tested. Identifying the enhancer region will lead to more information on the genetic control of ostia formation and provide insight into vertebrate heart development.
IMPACTS OF URBAN RUNOFF ON ROCKY INTERTIDAL ORGANISMS AT LITTLE CORONA MARINE LIFE
REFUGE, CALIFORNIAMatthew Scanlon, Velvet L. Park, Alexis Bueno Correa, Frank Campos, Emily Sanchez, William Hoese, Kristy Forsgren.
California State University, Fullerton, Fullerton, CA.
Rocky, intertidal organisms withstand a variety of abiotic stresses associated with tidal change including wave shock at high tide and ultraviolet radiation and desiccation at low tide. An emerging concern is the influence of freshwater urban runoff which varies in pH and temperature compared to ocean water and may contain harmful compounds.
We investigated the effects of runoff on intertidal species richness at Little Corona Marine Life Refuge at 3 sites: not influenced, indirectly influenced, and directly influenced by freshwater runoff. We hypothesized that sites with runoff would have lower species richness and salinity, as well as higher ammonia and nitrate levels. Thirty meter transects were placed in low, mid, and high intertidal zones at each site. Species richness was measured in three 1 m2 quadrats at 5 distances along each transect. Water quality was measured at 3 points along each transect. Species richness was not significantly different across sites. Ammonia, nitrate, and pH levels were higher while salinity was lower at sites influenced by runoff compared to the no-runoff site. Lower abundances of focal species were observed at sites influenced by runoff compared to the no-runoff site. Prevalence of crustacean and limpet species was also lower at runoff sites. Algae prevalence was higher at runoff sites than the no-runoff sites. Freshwater containing high nitrate and ammonia levels may affect rocky intertidal community structure in urban runoff-influenced areas where organisms are under stress; thus rocky intertidal communities may be used as indicators of habitat health.
EXPLORING NEW WATERS: BIOGEOGRAPHY AND OCEANOGRAPHIC CONTROLS OF THE SOUTHERN
CALIFORNIA CURRENT MIDWATER FISH COMMUNITYXochitl Rojas-Rocha, Peter Davison, Ana Lara-Lopez, Tais Castellano, J. Anthony Koslow.
Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA.
The midwater fish community of the southern California Current (CC) is abundant, diverse, and forms a key link between primary productivity and higher trophic organisms such as marine mammals and seabirds. Despite its major role in oceanic foodwebs, this fish community remains largely understudied. Our study examined samples of the southern CC’s midwater fish community to enhance understanding of the community’s structure and response to seasonal cycles and climate events such as El Niño and La Niña. Trawl samples were collected on quarterly California Cooperative Fisheries Investigation (CalCOFI) research cruises from 2010 to 2012. We studied the species composition and abundance of the midwater fish assemblage in the southern CC and its spatial and temporal variability relative to oceanographic conditions. Our findings contribute to the scientific community’s understanding of
an oceanic community that plays a critical role in oceanic foodwebs and is thus important to the general public which relies on commercial fisheries economically and for food.
SPECIES IDENTIFICATION GUIDE FOR EUPHAUSIIDS OF THE CALIFORNIA CURRENTTais Castellano1, Linsey Sala1, Pete Davison1, Andrea Miller2, Tony Koslow1.
Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, 2University of California, 1 Berkeley, Berkeley, CA.
Proper species identification is necessary and fundamental to study the biogeography, ecology, trophic interactions, and changes in ecosystem health and status. Euphausiids (or krill) are among the most abundant marine organisms, critical in the transfer of energy from the phytoplankton to higher trophic levels as a major prey of many species of fishes, squids, seabirds, and baleen whales. There are 39 known species of euphausiids in the California Current Ecosystem (CCE). Many of these species are morphologically very similar, and a guide is needed to correctly identify them. The goal of this project is to develop an identification guide for marine biologists, ecologists, and oceanographers to use when analyzing zooplankton samples from the CCE. The guide includes a key, a description, and a picture of each species with relevant field marks noted. Descriptions and illustrations of the characteristics are being taken from reference materials and journal articles. The guide is being tested with each of the 39 known euphausiids of the CCE in order to ensure that each species can be correctly identified. Preliminary tests have indicated positive efficacy for the guide. The Koslow lab will use this guide to study biogeography and responses to seasonal and climatic perturbations. We plan to make it available to other researchers to further our understanding of the ecological influences that different species have on the ecosystem and the food web.
COMPARING THE REEF FISH COMMUNITIES OF SHALLOW AND MESOPHOTIC CORAL REEFS OF WESTMAUI, HAWAIʻI Hulali Kinilau1, Erik Franklin2.
Chaminade University, Aiea, HI, 2Hawaii Institute of Marine Biology, Kane’ohe, HI.
1 Mesophotic reefs are coral ecosystems found in tropical and subtropical ocean depths of 30 m to greater than 100 m. These reefs contain corals, sponges, and algae as the dominant structural components and experience a low availability of light for photosynthesis due to their depth. The biological communities on shallow coral reefs are home to a diverse group of fish that comprise about 25% of all marine life, yet little is known about the fish communities on mesophotic reefs and how they compare to those of shallow reefs. To learn more about the fish communities on mesophotic reefs, we used unbaited and baited remote underwater stereo-videos (RUVs and BRUVs) to characterize reefs of west Maui in the Hawaiian Islands in 2012. We detail the methods used to analyze data generated by the RUVs and BRUVs and present preliminary results of fish community composition at these sites. We also compare the mesophotic reef fish communities to nearby shallow reef fish communities to determine similarities in composition.
Our results will contribute to a more holistic view of coral reef ecosystems across a broader depth range and improve our understanding of the relationship between biological communities of shallow coral reefs and mesophotic reefs.
PRELIMINARY SPATIAL DISTRIBUTION OF COPEPODS IN THE BIOLUMINESCENT BAY OF LAGUNA
GRANDE, FAJARDO, PUERTO RICOIsabel Sanchez1, Carlos Mota-Annexy1, Jamie Pierson2, Edwin A Hernandez-Delgado3.
Universidad Metropolitana, San Juan, PR, 2University of Maryland Center for Environmental Science, Cambridge, 1 MD, 3Center for Applied Tropical Ecology and Conservation, University of Puerto Rico, San Juan, PR.
As far as we know, copepod dynamics have been poorly documented in tropical bioluminescent bays. Copepods are the most abundant taxa in the zooplankton community and constitute an important key in the flow of energy through marine food webs. Our objective was to carry out a preliminary assessment of the spatial distribution of copepod species Acartia tonsa in relation to fluctuations in water quality parameters at the bioluminescent lagoon of Laguna Grande, Fajardo, Puerto Rico. Samples from 9 stations were analyzed beginning in the ocean and continuing through the connecting channel towards the end of the lagoon. On each station, the water-quality parameters (salinity, temperature, pH, turbidity, and oxygen concentration) were measured with an YSI-6280-V2. A 200 µm plankton net was towed for 1 minute at a constant speed to collect samples. Preliminary results suggested a statistically significant decline in copepod density with increasing water turbidity, declining oxygen concentration, and declining salinity.
HABITAT CHARACTERIZATION OF ASPARAGOPSIS TAXIFORMIS (LIMU KOHU) LINEAGESKanani Thompson, Mindy Mizobe.
Hawaii Institute of Marine Biology, Kaneohe, HI.
Limu kohu is a red alga found worldwide in warm-temperate and tropical oceans. In the Mediterranean Sea, limu kohu is considered an invasive nuisance species, while in Hawaii it is a valued food source that has disappeared from many coastlines. There are 4 known lineages (1, 2, 3, and 4) of limu kohu, and Hawai’i is the only place currently known to contain 3 out of the 4 lineages (1, 2, and 4). We wanted to characterize the habitats of the different lineages as a first step in identifying potential anthropogenic disturbances that could affect the presence of this valued resource.